The CDC recently issued new guidelines saying people who smoke and vape are at higher risk for more severe complications and hospitalization if they get COVID-19.

The CDC analyzed data from confirmed cases across the U.S. between mid-February and late March. It found about 78% of ICU coronavirus patients and 71% of other hospitalized COVID-19 patients had one or more reported underlying health conditions like lung disease, diabetes or heart disease — all of which have been linked to smoking.

Dr. Jonathan Winickoff is a professor of pediatrics at Harvard Medical School and director of translational research at the American Academy of Pediatrics. He says both smoking and vaping affect the body’s ability to fight off infections, and they compromise the immune system, making it more susceptible to COVID-19.

“I heard of a patient, 22 years old, who was hospitalized. And her only risk factor was that she was vaping. So this creates a huge problem for us as pediatricians, creates a lot of anxiety, I think, in terms of for parents and for teens themselves. So we don’t know everything there is to know about vaping and lung risk and COVID-19. But right now, what we’re seeing is very concerning,” Dr. Winickoff said.

Other systematic reviews have also shown higher risk for COVID-19 deaths or ICU cases among people who smoked or formerly smoked.

Meanwhile, the CDC continues to recommend that people who are sick, especially people with underlying health conditions, stay home except to get medical care.

Sick or not, staying home is something Matthew Myers, president of the Campaign for Tobacco-Free Kids, says could be an opportunity to quit smoking or vaping.

“Today, anything that puts your lungs at risk makes you more vulnerable,” Myers said. “What we’re encouraging parents to do is sit down with their teens, have an honest, open and objective conversation with them to make sure that teens understand that vaping is not a harmless activity, that it not only leads to addiction, potentially long-term addiction, but that there are other diseases associated with it.”